Jeep CJ, YJ, TJ - Weak Links, Strong Fixes

Jeep CJs, YJs, and TJs are some of the most recognized vehicles on the planet. Known for their unique look and mountain-goat-like agility, they seem to have more fans than Britney Spears. Or the inside of a hovercraft, take your pick.

Like any other mechanical device, or pop star, they do have their quirks. Some are design flaws and some are issues brought on by age and trail use. In this episode of "Weak Links, Strong Fixes" we delve into some of the issues that could face owners of these vehicles. Your experience may vary, but these are some of the issues that the Jeep pros tell us they deal with on a regular basis.

Weak link: AMC Model 20 two-piece axleshafts Models affected: '76-'86 CJWhat happens: The Model 20 isn't a bad axle overall (though some may argue that point), and by design it is easier to rebuild and set up than Spicer/Dana axles. Unfortunately, one of its weaknesses is that it uses two-piece axleshafts that are weaker than a comparable one-piece 'shaft because of its outer splines. Larger tires, rough terrain, and the addition of a locker can tax the two-piece axleshafts, often resulting in breakage. Strong fix: Many manufacturers offer one-piece axleshaft kits for the Model 20. One of those is Randy's Ring & Pinion, and theirs are forged, induction-hardened units made from 1541H alloy. They are available for wide track, narrow track, and (surprise!) Quadra-Trac axles. Each kit comes complete with studs, Timken bearings and National Seal inner and outer seals. Contact: Randy's Ring & Pinion, 866/245-2316, www.ringpinion.com

Weak link: Rusty frameModels affected: '80-'86 CJWhat happens: By design, the stock frames under these rigs tend to accumulate dirt and water. Because the frame is boxed, this captive mixture can flow to the rear of the frame, causing major rust. Attitude Performance in Arlington Heights, Illinois, says that it's not uncommon in the Rust Belt for the rear spring hangers to completely rust off. Strong fix: You may be able to graft in new frame pieces, but if you're in love with your Jeep, you can replace the entire frame with a new one from a company like Matkins. They offer the Extreme Frame that includes a lifetime warranty and is welded to the specifications of NASCAR and Super Truck. They also offer mandrel-bent Economy Frames. Another option: If your rear spring hangers rust off, you now have a great excuse to convert to a four-link/coilover suspension and skip the leaves altogether. Contact: Matkins, 406/248-3797, www.matkinsextreme.com

Weak link: Front axleshaft U-jointsModels affected: '72-'86 CJ and '87-'96 YJWhat happens: Most Dana 30 axleshafts used a small Spicer 260-X U-joint, which had a habit of failing regularly. To add insult to injury, collateral damage often included the axleshaft yoke.Strong fix: Many manufacturers offer upgrade kits for these axles, including Superior Axle & Gear. Their axleshafts are the same spline and diameter, but use a larger 297-X U-joint.Contact: Superior Axle & Gear, 888/522-2953, www.superioraxle.com

Weak link: SR-4, T-4, and T-5 manual transmissionsModels affected: '82-'86 CJWhat happens: These transmissions were notoriously weak. But hey, at least their gearing was crappy. The result was a gearbox with durability issues and lackluster off-highway performance. Strong fix: Retrofit is the key word here. Burnsville Off Road in Burnsville, Minnesota, often swaps in a TH400 automatic, while Clemson 4-Wheel Drive Center in Clemson, North Carolina, often utilizes a T-176 (which is actually found in some '80-'83 CJ's). Other options include a Ford T-18, NP435, SM465, SM420, NV3550, or the NV4500. No matter which of these you choose, Advance Adapters offers the bellhousing components and transfer case adapters to make them fit. Contact: Advance Adapters, 800/350-2223, www.advanceadapters.com

Weak link: Oiling systemModels affected: 304ci-, 360ci-, and 401ci-equipped CJ's What happens: These engines have a lousy lubrication system. One of the by-products is that the distributor gear doesn't get enough oil, thus it wears prematurely and fails. When this happens your jeeping day comes to a rapid halt. Strong fix: Attitude Performance in Arlington Heights, Illinois, tells us that they improve lubrication flow to the distributor gear by drilling and tapping a hole in the front of the block near the distributor gear so that a copper tube can be routed from an oil-pressure sending port at the front of the engine. The result is that the distributor gear gets a constant spray of life-giving oil.Contact: Attitude Performance, 847/593-0505, www.attitudeperformance.com

Weak link: Dana 35C rear axleModels affected: '89-'96 YJ, '97-'05 TJWhat happens: The Dana 35C rear axle is the Peugeot transmission of axles. Somewhat reliable for stock use, its reliability quickly becomes sketchy at best when you hit the trail, add larger tires, or look at it funny. We know-we've had one.Strong fix: The hot ticket is to swap it out for something beefier. The general consensus is a Dana 44 or a Ford 8.8 will do a great job for rigs equipped with up to 35-inch tires. If you absolutely must keep the 35C under your rig, fear not, because there are gobs of companies offering ways to make it better. Randy's Ring & Pinion is one of those, and they offer the Ultimate 35 kit that includes two Yukon heavy-duty alloy 30-spline axleshafts, carrier bearings, studs, axle bearings, and shims. Further, you can choose kits that include a Detroit, Ox, or ARB locker. Contact: Randy's Ring & Pinion, 866/245-2316, www.ringpinion.com

Weak link: Peugeot/BA10-15 five-speed manual transmissionModels affected: '87-'89 YJ What happens: This transmission is probably one of the most ridiculed gearboxes of all-time. Infamous for its unreliability, it also gained fame for its hard-to-service internal clutch slave. Strong fix: Get rid of it and swap in something good. Advance Adapters offers a number of bellhousings and transfer case adapters that offer the opportunity to upgrade (see "Weak Gearbox"). Contact: Advance Adapters, 800/350-2223, www.advanceadapters.com

Weak link: Vacuum actuator Models affected: '87-'95 WranglerWhat happens: When you shift the transfer case into four-wheel drive, a vacuum actuator is designed to move a collar laterally and engage the front axleshaft. Unfortunately, this component often fails for one reason or another. When this happens, the transfer case engages but the front axle doesn't. The result is no four-wheel drive. Strong fix: 4x4 Posi-Lok offers a kit that replaces the vacuum system and allows the driver to engage the shift collar and fork from inside the cab with simply a 1-inch pull on the 4x4 Posi-Lok cable. Contact: 4x4 Posi-Lok, 517/279-7177, www.4x4posi-lok.com

Weak link: Front suspension shacklesModels affected: '76-'86 CJ, '87-'95 YJWhat happens: On these vehicles, the shackles for the leaf-spring front suspension are located at the front of the leaves. One of the downsides to this setup is that whether you are on the road or trail, when the front tires come in contact with an obstruction, the impact is partially transmitted back to the frame via the solid rear pivot point. Further, this system creates unwanted handling issues as well as wandering. Strong fix: A shackle-reversal kit eliminates these issues by relocating the pivot point to the rear of the leaf springs. This allows the impacts to be better absorbed by the spring and shackle, which translates to a more natural suspension flow over an obstacle. It also offers a smoother ride and improved handling at higher speeds. There are a number of aftermarket companies manufacturing shackle-reversal kits. We talked to a number of shops, and they all spoke highly of the shackle-reversal kits manufactured by Mountain Off Road Enterprises (M.O.R.E.). One of the things that make them attractive is that they feature new front pivot brackets that are designed to move the front axle forward from the stock location. This helps keep the tire from contacting the fender during suspension compression. Contact: Mountain Off Road Enterprises, 970/625-0500, www.mountainoffroad.com

Weak link: Windshield framesModels affected: '87-'96 YJWhat happens: The windshield frames on these vehicles are notorious for rusting out, especially in the Rust Belt states. Strong fix: Don't plan on jeeping down to your local dealer for a new one, because they don't have them anymore. There are many aftermarket companies offering them, though, including Jeepglass.com. They can hook you up with a complete, ready-to-install windshield frame with glass and inner and outer seals for a little over $400. Further, they can even paint it for you for an additional fee. Contact: Jeepglass.com, 253/473-7691, www.jeepglass.com

Weak link: U-joint retaining strapsModels affected: All YJ and TJWhat happens: These light-duty straps are used to mount both the front and rear driveshafts to their respective axles. On the street they seem to hold up fine, but they often succumb to off-highway stresses. Strong fix: The hot ticket is to change out your yokes to ones featuring much beefier U-bolt-style mounts. Randy's Ring & Pinion offers everything you need to do this swap, no matter what factory Dana axles you have under your rig. Contact: Randy's Ring & Pinion, 866/245-2316, www.ringpinion.com

Weak link: Front driveshaftModels affected: '97-'05 TJWhat happens: These vehicles use a driveshaft with a non-greaseable front CV joint. Over time, these joints can dry out and eventually seize. When they seize, they can cause damage to the transfer case. "We've actually seen them split the transfer case in half when the CV seizes up" says Dan McKeag at Burnsville Off Road in Burnsville, Minnesota. Strong fix: Obviously, this is a problem you want to deal with before damage occurs. The best way to head off this problem is to have a new front driveshaft made that includes a greaseable CV joint. A quick call to a company like Driveshaftsuperstore.com can mean the difference between spending a little or a lot. Contact: Driveshaftsuperstore.com, 800/845-6326, www.driveshaftsuperstore.com

Weak link: Exhaust manifoldModels affected: '91-'99 TJ with the 4.0L engineWhat happens: The exhaust manifolds on these rigs are infamous for cracking. The question isn't if it's going to crack, it's when. Strong fix: Practically every aftermarket exhaust manufacturer offers a header for these engines. We've installed a few, and one we really liked was the unit manufactured by Borla. The header is constructed of T-304 stainless and includes a new gasket and all associated hardware. Contact: Borla Performance Industries, 877/462-6752, www.borla.com

Weak link: Double shifter bootModels affected: '97-'99 TJ with manual transmissionWhat happens: These TJs use a lower and an upper shifter boot. The combined resistance of these two boots makes moving the shift lever difficult, especially in cold weather. The problem seems to manifest itself most when shifting from 1st to 2nd and 3rd to 4th gears. Burnsville Off Road says that they've seen transmission synchros get damaged because the transmissions are used with gears not fully engaged because of the resistance. Often, the stiff shifting is misdiagnosed as a faulty AX-15 transmission. Strong fix: Some TJ owners remove the top shifter boot, which decreases the resistance and alleviates the problem, but it looks weird. The most popular method of freeing up the shifter is to make a small 1/8-inch cut in the lower boot, near the shift lever. Contact: Burnsville Off Road, 952/890-3990, www.burnsvilleoffroad.com

Weak link: Front antiroll-bar end linksModels affected: '97-'05 TJWhat happens: The antiroll-bar end links on these vehicles rate right up there reliability-wise with the Peugeot transmission and the 35C rear axle. They are a ball-and-socket type and they quickly wear out. Ours went out by 12,000 miles. The result is an aggravating rattling noise emanating from the front end of the vehicle as the ball bangs against the socket. Strong fix: Don't bother replacing them with stock end links, because they'll wear out as well. A better idea is to install some aftermarket quick-disconnect end links. After all, they'll not only get rid of the rattle, but they'll also allow you to quickly disconnect the front antiroll bar to enhance front suspension travel off-highway. An example is Superlift's quick-disconnects that they say generate a much-appreciated 5 inches of additional wheel travel when disconnected. Contact: Superlift Suspension Systems, 318/397-3000, www.superlift.com

Weak link: Climate control knobsModels affected: '00-'02 TJWhat happens: The twist-style climate-control knobs were introduced in 2000, and they replaced the sliding-style controls previously used. These knobs are a unitized assembly and have a high failure rate. The folks at Burnsville Off Road tell us that they've replaced scores of these units. Problems generally revolve around unresponsive or partially unresponsive operation. Strong fix: Sorry to break it to you, but like the failing seat cables, the only option is to purchase a new climate-control knob assembly from your local Jeep dealer. At least you now know why your knob isn't working. Contact: Your local Jeep dealer

Weak link: Seat pull strapsModels affected: '97-'99 TJWhat happens: Built in to the front of the seatbacks of the front seats are cables that allow you to tilt the seat forward to access the back seats without reaching behind the front seats to use the low-mounted lever. These cables have plastic ends that break, rendering the cable useless. Strong fix: Unfortunately, when these cables break, the only option is to remove the seats and disassemble them to get to the broken cable. Even though this is a common problem on the '97-'99 TJ, parts can only be acquired through Jeep dealers, sorry. Contact: Your local Jeep dealer

This is the fifth installment of a series that will examine some of the common problems of popular four-wheel-drive vehicles and how to fix 'em. Past installments included Chevy fullsize trucks and SUVs (May '04), Ford fullsize trucks and SUVs (Aug. '04), Dodge fullsize trucks and SUVs (Apr. '05), and Toyota pickups and 4Runners (July '05). In future issues we're going to put the spotlight on other four-wheel-drive trucks and SUVs.